1. Field of the Invention
The present invention relates to a cooling apparatus using boiling and condensing refrigerant, capable of cooling an exothermic body by heat radiation caused by repetitive boiling and condensing refrigerant.
2. Description of Related Art
One type of related cooling apparatus using boiling and condensing refrigerant is disclosed in U.S. patent application Ser. No. 08/790,015.
According to this related art, a heat insulating passage 110 is formed inside a refrigerant tank 100 as shown in FIG. 30. The heat insulating passage 110 is formed between a vapor passage 120 and a condensed liquid passage 130 to reduce the amount of heat transferred from an exothermic body through the vapor passage 120 to the liquid refrigerant in the condensed liquid passage 130. Accordingly, boiling of the refrigerant in the condensed liquid passage 130 is prevented, and the condensed liquid refrigerant in the condensed liquid passage 130 sent from a radiator can be stably supplied to the vapor passage 120.
According to the above related apparatus, however, if the temperature of the exothermic body increases, a part of the bubbles generated in the heat insulating passage 110 may flow back (return) to the vapor passage 120 via a communication passage 140. Accordingly, the boiling refrigerant surface in the vapor passage 120 may be filled with more bubbles, and the radiation performance of the apparatus may be compromised.
Furthermore, according to the above related apparatus, the refrigerant tank 100 is formed by an extruded material, and an extruded support wall 150 divides the refrigerant tank 100 into the vapor passage 120 and the condensed liquid passage 130. Further, in order to form the heat insulating passage 110, an extra support wall 160 is extruded. Thus, the extrusion performance may be compromised because a cross section of the refrigerant tank 100 is asymmetric. If another extra support wall to add an extra heat insulating passage is formed to make the refrigerant tank 100 symmetric, the apparatus may be increased in size by the extra heat insulating passage.